The present invention relates to a copolymeric prepolymer (hereinafter called as pre-copolymer) consisting of diallyl phthalate (hereinafter abbreviated as DAP) units and triallyl isocyanurate (hereinafter abbreviated as TAIC) units obtained by the radical copolymerization of DAP and TAIC, and to the method of producing the pre-copolymer.
Prepolymer is generally a polymer of relatively low molecular weight having unsaturated bonds in its own molecule, and is generally known as an intermediate substance such as those after molding further polymerized to be the finished polymer, or after adding other monomer(s), a cross-linking agent, etc. and molding further polymerized to be the finished polymer.
Hitherto, as the homopolymeric prepolymer of DAP, prepolymers of diallyl orthophthalate (hereinafter abbreviated as DAOP) or diallyl isophthalate (hereinafter abbreviated as DAIP) have been known and they are used as a molding material because of their favorable stability, and the thus obtained finished polymeric substances are used as a material for several electric parts, for instance, connectors, switches, plugs, magnet cores, base plates for printed circuits because of their excellent electricals properties as well as their moderate heat-stability.
Although these polymeric substances of DAP have the above-mentioned favorable properties, they have still defects in heat-stability in higher temperature conditions such as losing its own weight or thermally decomposing suddenly and violently at a high temperature, and accordingly, their use-conditions are restricted in certain fields of application.
The inventors of the present invention made studies on the improvement of the above-mentioned defects in the finished polymeric materials by adding TAIC monomer in the production of pre-polymer of DAP, and have completed the present invention.